Sharing volume between Docker containers

Question

I am using Docker to deploy some services and I want to share the Docker volumes between different containers.

Suppose I have a Docker container A which mounts a volume a

Answer 1

You may find a lot of pointers mentioning data-only containers and --volumes-from. However, since docker 1.9, volumes have become first class citizens, they can have names, and have more flexibility:

It's now easy to achieve the behavior you want, here's an example :

1. Create a named data volume with name service-data:

   docker volume create --name service-data
   

2. You can then create a container that mounts it in your /public folder by using the -v flag:

   docker run -t -i -v service-data:/public debian:jessie /bin/bash
   

   For testing purpose we create a small text file in our mapped folder:

   cd public
   echo 'hello' > 'hello.txt'
   

3. You may then attach your named volume to a second container, but this time under the data folder:

   docker run -t -i -v service-data:/data debian:jessie /bin/bash
   ls /data       #-->shows "hello.txt"
   

Just remember, if both containers are using different images, be careful with ownership and permissions!